Emulsions of ionically cross-linked resins and methods for making them



EMULSIONS F IONICALLY CROSS-LINKED REfilNS AND METHODS F OR MAKING THEMGeorge L. Brown, Moorestown, N. 3., and Benjamin B.

Kine, Levittown, la., assignors to Rohm & Haas Ionipany, Philadelphia,Pa., a corporation of Delaware No Drawing. Application April 23, 1954,Serial No. 425,331

12 Claims. (Cl. 26029.6)

This invention relates to the preparation and use of stable aqueousdispersions of dissociated ionically cross-linked water-insolubleresins. It relates to aqueous dispersions which are stable and which areparticularly suited as vehicles for surface-coatings and for theproduction of dry, non-blocking free films or pellicles. It relates todispersions in certain aqueous media of waterinsoluble copolymers of (a)the lower alkyl esters of acrylic and methacrylic acids and (b) acrylic,methacrylic and/ or itaconic acids, which copolymers are crosslinked bymeans of certain polyvalent metals as is described in greater detailbelow. This application is a continuation-in-part of our copendingapplication Serial No. 336,632, filed February 12, 1953, now abandoned.

An object of this invention is to provide dispersions which, whendeposited as thin layers or films and then dried, provide continuousfilms which are tough, dry, and non-blocking, and which arecharacterized by a lack of cold-flow. A further object is to providesurfacecoating dispersions which, on evaporation in thin layers, yieldfilms which are continuous and cohesive and have the properties usuallyassociated with films of thermoset resins. That is to say, an object isto provide dispersions of resins which are actually cross-linked butwhich, despite their being cross-linked, coalesce during a drying periodand form cohesive and continuous films. A further object is to coatmaterials by means of such dispersions and to prepare free films ofresins from such dispersions.

These and other objects are most advantageously attained by emulsifying,with a non-ionic emulsifying and/ or dispersing agent, andcopolymerizing-preferably under the influence of a peroxidicfree-radical catalyst a mixture which contains at least one of each ofthese two kinds of polymerizable materials: (a) esters of acrylic andmethacrylic acids and (b) acrylic acid, methacrylic acid, and itaconicacid, and then neutralizing at least some of the free carboxyl groups inthe copolymer by means of certain oxides, hydroxides, or salts of apolyvalent metal. Less advantageously, water-insoluble copolymers of theaforesaid two types of polymerizable materials produced in any other waymay be dispersed in water by means of non-ionic dispersing agents.

The resultant products are to all intents and purposes dispersions ofcross-linked resins because pairs of carboxyl groups in the variousmolecular chains are joined together; i. e., are cross-linked, by theatoms of the polyvalent metals. As long as water is present, ionizationoccurs and the positive ions of the cross-linker and the negative ionsof the resin have a certain degree of mobility so that thecross-linkages are not fixed or rigid. As a result, the resin particlesin a film of the dispersion can and do coalesce as drying takes place.However, as the water is removed by evaporation or force-drying, themobility of the ions is gradually reduced; and when substantially all ofthe water is removed, the ions become immobilized. Then the metals andthe long chains of resin become chemically bound in a rigid, fixed, andcrosslinked molecular configuration.

" nited States Patent 9 The dispersions of this invention are in realitythose of dissociated ionically cross-linked resins and they aredecidedly different from the dispersions of resins which arecross-linked by means of a polyvinyl compound such as divinyl-benzene.The latter kind of dispersions contains resins which are rigidlycross-linked even when they are dispersed in the aqueous phase andconsequently on drying they deposit the resin in the form of discreteparticles which do not effectively coalesce and which form weak ordiscontinuous films.

Furthermore, the dispersions of this invention give rise to films whichare not subject to cold-flow and which do not block in contrast todispersions of the same esters and acids which are not ionicallycross-linked. Thus, the instant products have the advantages of boththermoplastc resin dispersions and thermoset resin dispersions withoutthe chief disadvantages of either.

The dispersions are preferably prepared by emulsifying a mixture of a)one or more monomeric esters of acrylic and/or methacrylic acid and (b)monomeric arcrylic, methacrylic and itaconic acid or mixtures of theseacids in water and polymerizing the mixture while it is in theemulsified form. It is essential that a non-ionic emulsifying ordispersing agent be used. The monomeric esters of acrylic andmethacrylic acids which have proven to be most satisfactory are thealkyl esters in which the alkyl group contains one to eight carbon atomsand'which are exemplified by the following: methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, isoamyl, tert-amyl,hexyl, heptyl, n-octyl, and 2-ethylhexyl acrylates and methacrylates andisomers of these. From 0.25% to 25% on a molar basis or preferably from0.5% to 12%-of the acid is employed.

The non-ionic emulsifiers or dispersing agents that may be used forpreparing the monomeric emulsions before copolymerization or dispersionsof the polymer after poly merization include the following:alkylphenoxypolyethoxyethanols having alkyl groups of about seven toeighteen carbon atoms and 6 to 60 or more oxyethylene units, such asheptylphenoxypolyethoxyethanols, octylphenoxypolyethoxyethanols,methyloctylphenoxypolyethoxyethanols, nonylphenoxypolyethoxyethanols,dodecylphenoxypolyethoxyethanols, and the like; polyethoxyethanolderivatives of methylene linked alkyl phenols; sulfur-containing agentssuch as those made by condensing 6 to 60 or more moles of ethylene oxidewith nonyl, dodecyl, tetradecyl, t-dodecyl, and the like mercaptans orwith alkylthiophenols having alkyl groups of six to fifteen carbonatoms; ethylene oxide derivatives of long-chained carboxylic acids, suchas lauric, myristic, palmitic, oleic, and the like or mixtures of acidssuch as found in tall oil containing 6 to 60 oxyethylene units permolecule; analogous ethylene oxide condensates of long-chained alcohols,such as octyl, decyl, lauryl, or cetyl alcohols, ethylene oxidederivatives of etherified or esterified polyhydroxy compounds having ahydrophobic hydrocarbon chain, such as sorbitan monostearate containing6 to 60 oxyethylene units, etc.; block copolymers of ethylene oxide andpropylene oxide comprising a hydrophobic propylene oxide sectioncombined with one or more hydrophilic ethylene oxide sections.

The dispersions can be prepared at temperatures from 0 C. to about 100C., but intermediate temperatures are much preferred. Thus, with theesters in which the alkyl group contains one to four carbon atoms atemperature from about 10 C. to about 60 C. is employed whereas a highertemperature; e. g., 30 C. to C., is recommended when those esterscontaining five to eight carbon atoms in the alkyl group arecopolymerized. Peroxidic free-radical catalysts, particularly catalyticsystems of the redox type, are recommended. Such systems, as is wellknown, are combinations of oxidizing agents and reducing agents such asa combination of potassium persulfate and sodium metabisulfite. Othersuitable peroxidic agents include the per-salts such as the alkali metaland ammonium persulfates and perborates, hydrogen peroxide, organichydroperoxides such as tert-butyl hydroperoxide and cumenehydroperoxide, and esters such as tert-butyl perbenzoate. Other reducingagents include water-soluble thiosulfates and hydrosulfites and thesaltssuch as the sulfates-of metals which are capable of existingin'more than one valence state such as cobalt, iron, nickel, and copper.The most convenient method of preparing the copolymer dispersionscomprises agitating an aqueous suspension of a mixture ofcopolymerizable monomers and a redox catalytic combination at roomtemperature without the application of external heat. The amount ofcatalyst can vary but for purposes of efficiency from 0.01% to 1.0%,based on the weight of the monomers, of the peroxidic agent and the sameor lower proportions of the reducing agent are recommended. In this wayit is possible to prepare dispersions which contain as little as 1% andas much as 60% of the resinous copolymer on a weight basis. It is,however, more practical-hence preferred-to produce dispersions whichcontain about 30%50% resin-solids.

As indicated above, the instant products are dispersions of certaindescribed esters and acids. It is also within the spirit and scope ofthis invention to substitute for some of the acrylic or methacrylicesters defined above another copolymerizable monoethylenicallyunsaturated compound such as one which contains a single vinylidenegroup,

CHz---C Such compounds include vinyl chloride, vinylidene chloride,styrene, vinyltoluene, vinylnaphthalene, higher alkyl esters of acrylicand methacrylic acids such as lauryl and octadecyl acrylates andmethacrylates, and aryl esters such as benzyl and phenylethyl acrylatesand methacrylates. Obviously, such copolymerized materials exert' theirown influence on the properties of the films which are obtained. Thus,copolymerized styrene makes for greater hardness while octadecylacrylate makes for softness and flexibility. This invention, therefore,embraces ionically cross-linked copolymers which contain anothercopolymerized monoethylenically unsaturated compound and especially onehaving a vinylidene group,

in addition to the acrylic or methacrylic ester and the acrylic,methacrylic or itaconic acid. In such products the amount ofcopolymerized acid should be 0.25 molar percent and the amount ofestershould be greater on a molar basis than the amount of the thirdcopolymerized compound.

Next, free carboxyl groups of the copolymer are neutralized; and this isdone by adding a basic compound of a polyvalent metal which forms saltswith the carboxyl groups of the copolymer. Oxides or hydroxides ofbarium, calcium, magnesium, and strontium have been em ployed for thispurpose and all produced dispersions which deposited films ofoutstanding properties. Hydroxides of aluminum, lead and zirconium mayalso be used. It must also be pointed out that the basic salts ofpolyvalent metals and their salts of Weak acids (which are in effectbasic compounds when in the aqueous dispersions) have been usedsuccessfully, such as the normal and basic acetates of barium, calcium,cadmium, cerium,.strontium, zirconium, lead, cobalt (ic and cos),chromium (ic and ous), copper (ic), zinc, magnesium, iron (ous),manganese (ous), mercury (ic), and nickel (ic and ous). Tartrates,citrates, and oxalates may be used, such as stannous tartrate andtitanium oxalate. Basic aluminum acetate, basic aluminum formate andbasic zirconyl acetate are especially valuable for ionicallycross-linking the resins. What is required is that a sufficient numberof carboxyl groups be converted into salt polymers.

groups of the polyvalent cations so that, on removal of water, thecations link pairs of carboxyl groups together and thus insolubilize theresin. For this purpose it has been found that the acid groups of thecopolymers must be converted to salt groups to such an extent that atleast 0.25% and preferably 0.5% or more, on a molar basis, of all of thecopolymerized units in the final copolymer are salt groups. Thus,substantially all of the carboxyl groups in a copolymer containing only0.25 to 0.5 molar percent of copolymerized acid must be neutralized. Inthe case of a copolymer which contains a greater proportion ofcopolymerized acid; i. e., up to 25 molar percent, it is not necessary,although it is desirable, that all of the carboxyl groups be convertedto salt groups. But it is always necessary that enough of them beconverted to salt groups so as to provide the minimum number mentionedabove.

The basic metallic compounds which are used to neutralize the carboxylgroups of the copolymers and thus convert them into salt groups arethose of divalent and trivalent metals which have at least a solubilityin water of 0.0006 grams per cc. Actually, only two valences of thetrivalent metals may be involved in the neutralization so that thecompounds of trivalent metals may react, as far as this invention isconcerned, as if they were compounds of divalent metals. Therefore,

what is required is that the copolymer be reacted with and neutralizedby at least 0.125 mole and preferably from 0.25 mole to 12.5 moles ofthe basic metallic compound for every hundred moles of copolymerizedester and acid. That is to say, the number of moles of basic metalliccompound which are reacted with the copolymer are from 0.125 to 12.5percent of the total number of moles of the ester and acid which arecopolymerized. Any insoluble excess of metallic oxide, hydroxide, orbasic salt which is employed over the amount which reacts with thecopolymer can be readily separated from the copolymer dispersion by suchmeans as filtration or decantation.

The highly soluble basic salts have the following advantages over theoxides and hydroxides of relatively low solubility. They are rapid intheir cross-linking action. They are easily distributed uniformlythrough the resin dispersions in controlled amounts. They are easier tohandle since they can be dissolved in aqueous solutions and it isunnecessary to grind to a dust as in the case of relatively insolublematerial like the oxides and hydroxides. They involve on that accountless of a health hazard. The highly soluble basic salts produce filmsand other masses of better transparency and other optical properties.They do not settle out of the dispersions during storage thereof. Theoxides and hydroxides 'are prone to do this on standing and theyfrequently form cloudy, translucent films or the like instead of beingclear and transparent. In addition, the basic salts are generally threeto five times as efficient in cross-linking as the salts of weak acids.Accordingly, the basic salts are the preferred groups of cross-linkingcompounds.

In order to provide resinous surface-coatings or free films which on theone hand are cross-linked and are consequently water-insoluble andchemical-resistant and which on the other hand are continuous, stronglycohesive, and of high tensile strength, it is essential, first, that thecross-linked copolymer be in the form of a dispersion and, second, thatthe dispersed copolymer be in the form of dissociated ionicallycross-linked salt of a polyvalent cation. Hence, this invention is notconcerned with dispersions of copolymers which are organicallycross-linked by polyvinyl organic compounds because such dispersions donot form cohesive films on mere air-drying at room temperatures.Furthermore, it is not at all concerned with organic solutions of linearNor does this invention involve alkali metal salts or ammonium salts ofcopolymers, none of which is cross-linked and all of which arewater-soluble or at least water-swellable. Such water-sensitive salts ofcopolymers have long been known and while they have certain merit andutility, they are not cross-linked and do not give rise to the kind offilms or surface-coatings with which this invention is concerned.

When employed as surface-coatings, the dispersions of the presentinvention are readily applied by conventional means such as brushing,spraying, dipping, roller-coating, padding and the like. The films arethen dried either by evaporation or by the application of heat. Whileheating of the coating is unnecessary, it does accelerate thecross-linking and in general enhances the adhesion of the films.Temperatures up to the boiling point of the aqueous phase of thedispersions can be used; and, since cross-linking takes place during thedrying period, there is no particular reason for further heat-treatingthe dried films. Free films are also made readily by conventionalmethods as, for example, by casting, or by coating a drum followed bystripping of the film from the coated surface.

The following examples, in which all parts are by weight, serve toillustrate the preparation and properties of the products of thisinvention.

Preparation of dispersed copolymers A. The following components wereplaced in a flask equipped with a mechanical stirrer and thermometer:

71.25 parts ethyl acrylate 217 parts water 6.43 parts non-ionicdispersing agent (a 70% aqueous solution of atert-octylphenoxypolyethoxyethanol containing an average of about 35oxyethylene units in the molecule) The mixture was cooled to 15 C. andthere were added 0.09 part of ammonium persulfate and 0.12 part ofsodium hydrosulfite. The mixture was agitated; and the exothermicpolymerization soon began, as evidenced by a rise in temperature. Theaddition of 3.75 parts of acrylic acid was at once begun and continuedover a period of five minutes during which time the temperature roseabout degrees. The temperature rose rapidly thereafter and reached 60 C.in 10 minutes at which point an ice-bath was applied. The mixture wasthereby cooled to 38 C. in minutes at which point the icebath wasremoved and to the mixture was added 0.78 of tert-butyl hydroperoxidedissolved in 6 parts of water. The resultant mixture was further stirredfor 30 minutes.

B. in a similar manner a dispersion of a copolymer of ethyl methacrylateand acrylic acid was made. The only departures from the proceduredescribed in part A above were that ethyl methacrylate was substitutedfor the ethyl acrylate and ferrous sulfate was added at the beginning insuch an amount as to provide 3 p. p. m. of ferrous ion based on themixture of monomers.

C. In another instance, a mixture of 47.5 parts of ethyl acrylate, 3parts of non-ionic dispersing agent, and 100 parts of water was cooledto 15 C. and then agitated. Then .085 part of ammonium persulfate and.08 part of sodium hydrosulfite were added. As soon as the temperaturebegan to rise, 2.5 parts of itaconic acid, dissolved in 44 parts ofwater, was added over a period of 8 minutes. As polymerizationproceeded, the temperature rose in 17 minutes to a maximum of 56 C. Thedispersion was stirred until it reached room temperature.

D. An emulsion of butyl acrylate and acrylic acid was made by the methoddescribed in part A above for the copolymerization of ethyl acrylate andacrylic acid except that an ice-bath was applied when the temperaturereached 50 C.

When higher alkyl esters; e. g., 2-ethylhexyl acrylate, are employed, itis recommended that somewhat higher temperatures, of the order of 70-80C., be used. And under such conditions it is further recommended thatthe reactor be equipped with a reflux condenser.

E. Dispersions of copolymers containing two or more esters of acrylicand/or methacrylic acid are made in a similar way. Thus, the procedureof part A above was followed with the exception that 71.25 parts of amixture of 6 moles of ethyl acrylate and 4 moles of methyl methacrylatewas used in place of the single ester, ethyl acrylate, of part A.

Preparation of ionz'cally cross-linked copolymers All or" thedispersions which were prepared as abovedescribed were divided intoportions and the individual portions were treated at room temperaturewith the following basic compounds in such amounts as were equivalent totwice the number of moles of copolymerized acid present: Al(OH)3,Al(OOCCH3)2OH, Al(OOCCH3)2(OOCH), Ba(OH)z, Ca(OH)2, Mg'O, Sr(OH)2,Mg(OOCCHs)2, Mg(OH)2, Pb(OOCCH3)2, ZrO(OOCH)2. After two hours thedispersions were filtered and samples of each were flowed on glass andthe films were allowed to dry. In all cases the dried films weretack-free and were free of cold-flow. Also, all of the films wereinsoluble in toluene, although they imbibed the solvent and swelledsomewhat.

In contrast with the above, portions of the dispersion which were nottreated with the polyvalent metallic cross-linking agents (blanks)formed films which blocked, had cold-flow, and were completely solublein toluene.

The dispersions of this invention are especially useful for thedeposition of flexible surface-coatings which are clear or which can beopacified and/or colored by the incorporation of dyes or pigments. Thedispersions have been employed in the coating of rigid materials such aswood and metals. Also, various kinds of paper, such as wrapping paperand wallpaper, have been coated and thus protected and decorated. Thefeel and body of fabrics have been much improved by impregnation withthese dispersions. Coatings for leather made from the dispersions werecharacterized by excellent appearance and very desirable flexibility atlow temperatures. The free films which are flexible and strong and whichare resistant to water and chemicals find a ready use as wrappers foroily, greasy, or corrosive articles.

We claim:

1. As a new composition of matter, an aqueous medium comprisingdispersed therein (1) a non-ionic emulsifier, (2) a water-insolublecopolymer containing, in the polymer mol cule, units of at least oneester of an acid selected from the group consisting of acrylic andmethacrylic acids and 0.25 to 25 molar percent of carboxylcontainingmonomeric units derived from at least one member of the class consistingof acrylic, methacrylic, and itaconic acids, and (3) a basic metalliccompound, in an amount from 0.125 to 12.5 molar percent based on theweight of the copolymer, selected from the class consisting ofpolyvalent metal salts of weak acids, basic salts of polyvalent metals,the oxides and hydroxides of barium, calcium, magnesium, and strontium,and the hydroxides of aluminum, lead, and zirconium.

2. As a new composition of matter, an aqueous medium containingdispersed therein (1) a non-ionic emulsifier, (2) a copolymercontaining, in the polymer molecule, 75 to 99.75 molar percent ofmonomeric units derived from at least one member of the class consistingof the alkyl esters of acrylic and methacrylic acids in which the alkylgroup of the ester contains one to eight carbon atoms and 0.25 to 25molar percent of carboxyl-containing monomeric units derived from atleast one member of the class consisting of acrylic, methacrylic, anditaconic acids, and (3) a basic metallic compound, in an amount from0.125 to 12.5 molar percent based on the weight of the copolymer,selected from the class consisting of polyvalent metal salts of weakacids, basic salts of polyvalent metals, the oxides and hydroxides ofbarium, calcium, magnesium, and strontium, and the hydroxides ofaluminum, lead, and zirconium.

3. As a new composition of matter, an aqueous medium comprisingdispersed therein (1) a non-ionic emulsifier, (2) a water-insolublecopolymer containing, in the polymer molecule, units of at least oneester of an acid selected from the group consisting of acrylic andmethacrylic acids and 0.25 to 25 molar percent of carboXyl-containingmonomeric units derived from at least one member of the class consistingof acrylic, methacrylic, and itaconic acids, and (3) a basic salt of apolyvalent metal in an amount from 0.125 to 12.5 molar percent based onthe weight of the copolymer.

4. A composition as defined in claim 3 in which the basic salt is basicaluminum acetate.

5. As a new composition of matter, an aqueous medium containingdispersed therein (1) a non-ionic emulsitier, (2) a copolymercontaining, in the polymer molecule, 75 to 99.75 molar percent ofmonomeric units derived from at least one member of the class consistingof the alkyl esters of acrylic and methacrylic acids in which the alkylgroup of the ester contains one to eight carbon atoms and 0.25 to 25molar percent of carbonyl-containing monomeric units derived from atleast one member of the class consisting of acrylic, methacrylic, anditaconic acids, and (3) a basic salt of a polyvalent metal in an amountfrom 0.125 to 12.5 molar percent based on the weight of the copolymer.

6. As a new composition of matter, an aqueous medium containingdispersed therein (1) a non-ionic emulsitier, (2) a copolymercontaining, in the polymer molecule, 75 to 99.75 molar percent of ethylacrylate and 0.25 to 25 molar percent of acrylic acid, and (3) 0.125 to12.5 molar percent, based on the weight of the copolymer, of calciumhydroxide.

7. As a new composition of matter, an aqueous medium containingdispersed therein (1) a non-ionic emulsifier, (2) a copolymercontaining, in the polymer molecule, (a) 75 to 99.75 molar percent of amixture of six moles of ethyl acrylate and four moles of methylmethacrylate, and (b) 0.25 to 25 molar percent of methacrylic acid, and(3) 0.125 to 12.5 molar percent, based on the weight of the copolymer,of basic aluminum acetate.

8. A process for making a dispersion of a resin which comprisesincorporating a basic metallic compound in dispersed condition, in anaqueous medium containing dispersed therein (1) a non-ionic emulsifierand (2) a copolymer containing, in the polymer molecule, units of atleast one ester of an acid selected from the group consisting of acrylicand methacrylic acids and 0.25 to 25 molar percent ofcarboXyl-containing monomeric units derived from at least one member ofthe class consisting of acrylic, methacrylic, and itaconic acids, thebasic me- Q b tallic compound being selected from the class consisting.of polyvalent metal salts of Weak acids, basic salts of polyvalentmetals, the oxides and hydroxides of barium, 7

calcium, magnesium, andstrontium, and the hydroxides of aluminum, lead,and zirconium, and being added in an amount from 0.125 to 12.5 molarpercent based on the weight of the copolymer.

9. A process for making a dispersion of a resin which comprisesincorporating calcium hydroxide in dispersed condition, in an aqueousmedium containing dispersed therein (1) a non-ionic emulsifier and (2) acopolymer containing, in the polymer molecule, to 99.75 molar percent ofethyl acrylate and 0.25 to 25 molar percent of acrylic acid, the amountof calcium hydroxide incorporated being from 0.125 to 12.5 molarpercent, based on the weight of the copolyrner.

10. A process for making a dispersion of a resin which comprisesincorporating basic aluminum acetate in dispersed condition, in anaqueous medium containing dispersed therein (1) a polymer containing, inthe polymer molecule, 75 to 99.75 molar percent of ethyl acrylate and0.25 to 25 molar percent of acrylic acid, the amount of basic aluminumacetate incorporated being from 0.125 to 12.5 molar percent, based onthe weight of the copolymer.

11. A process for making a dispersion of a resin which comprisesincorporating calcium hydroxide in dispersed condition, in an aqueousmedium containing dispersed therein (1) a non-ionic emulsifier and (2) acopolymer containing, in the polymer 'rnolecule, (a) 75 to 99.75 molarpercent of a mixture of six moles of ethyl acrylate and four moles ofmethyl methacrylate and (b) 0.25 to 25 molar percent of methacrylicacid, the amount of calcium hydroxide incorporated being from 0.125 to12.5 molar percent, based on the weight of the copolymer.

12. A process for making a dispersion of a resin which comprisesincorporating basic aluminum acetate in dispersed condition, in anaqueous medium containing dispersed therein (1) a non-ionic emulsifierand (2) a copolymer containing, in the polymer molecule, (a) 75 to 99.75molar percent of a mixture of six moles of ethyl acrylate and four molesof methyl methacrylate and (b) 0.25 to 25 molar percent of methacrylicacid, the amount of basic aluminum acetate incorporated being from 0.125to 12.5 molar percent, based on the weight of the copolymer.

References Cited in the file of this patent FOREIGN PATENTS 580,250Great Britain Dec. 20, 1944 non-ionic emulsifier and (2) a co-

1. A NEW COMPOSITION OF MATTER, AN AQUEOUS MEDIUM COMPRISING DISPERSEDTHEREIN (1) A NON-IONIC EMULSIFIER, (2) A WATER-INSOLUBLE COPOLYMERCONTAINING, IN THE POLYMER MOLECULE, UNITS OF AT LEAST ONE ESTER OF ANACID SELECTED FROM THE GROUP CONSISTING OF ACRYLIC AND METHACRYLIC ACIDSAND 0.25 TO 25 MOLAR PERCENT OF CARBOXYLCONTAINING MONOMERIC UNITSDERIVED FROM AT LEAST ONE MEMBER OF THE CLASS CONSISTING OF ACRYLIC,METHACRYLIC, AND ITACONIC ACIDS, AND (3) A BASIC METALLIC COMPOUND, INAN AMOUNT FROM 0.125 TO 12.5 MOLAR PERCENT BASED ON THE WEIGHT OF THECOPOLYMER, SELECTED FROM THE CLASS CONSISTING OF POLYVALENT METAL SALTSOF WEAK ACIDS, BASIC SALTS OF POLYVALENT METALS, THE OXIDES ANDHYDROXIDES OF BARIUM, CALCIUM, MAGNESIUM, AND STRONTIUM, AND THEHYHDROXIDES OF ALUMINUM, LEAD, AND ZIRCONIUM.